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Philco Tone Control 635 - Printable Version

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Philco Tone Control 635 - Frank - 12-11-2007

I need some help with the tone control on my Philco 635 chassis. (table model set). I removed what looks like a single capacitor from the tone control. I believe that each end of the capacitor was connected to the two terminals that are on the control, but am not sure if this is correct. I also am not sure of what the value of the capacitor was.

The wiring on this set was messed with, and I do not know which lead connects to where.

I would appreciate any help in connecting this tone control to the circut, and also, what value part should be in the control itself.

Thanks,
Frank.

- Carl Travis - 12-11-2007

Hi Frank,
On this schematic, #60 is the tone control and #61 is the .02uf capacitor contained in the tone control:
http://www.nostalgiaair.org/PagesByModel/814/M0013814.pdf

- Frank - 12-11-2007

Thanks! Wasn't sure about that part value.

Do you know which leads on the tone control I should connect the two chassis leads to? One goes to another .02 mfd cap that is located on the other side of the chassis. I just am not sure which of the two control terminals should get that connection. Then the other wire obviously would connect to the other terminal.

- Carl Travis - 12-11-2007

Frank,
There are 3 terminals in the tone control.
The first is not connected to anything.
The lead from the middle terminal would connect at the junction of #45, 20K ohm resistor and the #46 .02uf capacitor.
The other lead would connect to the plate pin of your 42 output tube where the the 61A, .003uf capacitor also attaches.

- Frank - 12-11-2007

I might have a production variation on my tone control. It only has two terminals visible from the back of the control. Each terminal connects to that internal capacitor...

- Frank - 12-12-2007

I took another look at the control, and now see what you mean by a terminal that is not connected. My tone control has the hole for the terminal, but not the connector. It didn't occur to me that the hole was where the unused terminal would be. Sometimes it's right in front of you and you just can't see it!

I am still confused by the capacitor in the tone control though. On the schematic, it shows one lead of it connected to the switch. But there were two wires comming from the tar holder where the capacitor was, and each wire was connected to a terminal lead on the control. I am having a hard time understanding why they did not show it this way on the schematic, and want to be sure that connecting the .02 mfd cap to each lead of the switch is correct.

Again, thanks for your help!